A beam is a structural element that is capable of withstanding load primarily by resisting bending. The bending force induced into the material of the beam as a result of the external loads is called a bending moment.
The magnitude of the bending moment along the length of a beam varies depending on the location and type of supports on which the beam is located. A positive bending moment induces compressive forces above the neutral axis, while tensile forces are induced in the material below the neutral axis. The compressive and tensile forces result in shortening and lengthening of the material respectively above and below the neutral axis. Internally, beams experience compressive, tensile and shear stresses as a result of the loads applied to them
By stretching and bending/contracting a resting beam the section between supports of the beam, called span, varies in length. The span is a significant factor in finding the strength and size of a beam as it determines the maximum bending moment and deflection.
There is a mechanical energy required to disassemble a beam or any other object into separate parts that is called binding energy. Binding energy represents the mechanical work which must be done in acting against the forces which hold an object together while disassembling the object into component parts. By stretching and bending a resting beam the binding energy of the beam is affected.
A beam can vibrate or oscillate about an equilibrium point. The oscillations may be periodic or can be random. Damping dissipates the energy and therefore the oscillating beam will eventually come to rest. A mechanical system set off with an initial input vibrates freely at one or more of its natural frequencies and damp down to zero. When an alternating force or motion is applied to a mechanical system the frequency of the vibration is the frequency of the force or motion applied, with order of magnitude being dependent on the actual mechanical system.
A vibration in a string is a wave. Usually a vibrating string produces a sound whose frequency in most cases is constant. Therefore, since frequency characterizes the pitch, the sound produced is a constant note. The provided apparatus consists of a “string vibration mechanism”.